Vitamin D deficiency modulates Graves' hyperthyroidism induced in BALB/c mice by thyrotropin receptor immunization.
TSH receptor (TSHR) antibodies and hyperthyroidism are induced by immunizing mice with adenovirus encoding the TSHR or its A-subunit. Depleting regulatory T cells (Treg) exacerbates thyrotoxicosis in susceptible BALB/c mice and induces hyperthyroidism in normally resistant C57BL/6 mice. Vitamin D plays an important role in immunity; high dietary vitamin D intake suppresses (and low intake enhances) adaptive immune responses. Vitamin D-induced immunosuppression may enhance Treg. Therefore, we hypothesized that decreased vitamin D intake would mimic Treg depletion and enhance hyperthyroidism induced by A-subunit adenovirus immunization. BALB/c mice had a reduced ability vs. C57BL/6 mice to generate the active metabolite of vitamin D (1,25-dihydroxyvitamin D3). Vitamin D deficiency induced subtle immune changes in BALB/c (not C57BL/6) mice. Compared with mice fed regular chow, vitamin D-deprived BALB/c mice had fewer splenic B cells and decreased interferon-gamma responses to mitogen and lacked memory T-cell responses to A-subunit protein. However, vitamin D deficiency did not alter TSHR antibody responses measured by ELISA, TSH binding inhibition, or cAMP generation from TSHR-expressing cells. Unexpectedly, compared with vitamin D-sufficient mice, vitamin D-deficient BALB/c mice had lower preimmunization T(4) levels and developed persistent hyperthyroidism. This difference was unrelated to the immunological changes between vitamin D-deficient or -sufficient animals. Previously, we found that different chromosomes or loci confer susceptibility to TSHR antibody induction vs. thyroid function. Our present studies provide evidence that an environmental factor, vitamin D, has only minor effects on induced immunity to the TSHR but directly affects thyroid function in mice.
Misharin
Alexander
A
Autoimmune Disease Unit, Cedars-Sinai Research Institute and University of California Los Angeles, UCLA School of Medicine, Los Angeles, CA 90095, USA.
Hewison
Martin
M
Chen
Chun-Rong
CR
Lagishetty
Venu
V
Aliesky
Holly A
HA
Mizutori
Yumiko
Y
Rapoport
Basil
B
McLachlan
Sandra M
SM
D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000235:genetics / Q000378:metabolism; D000256:Adenoviridae / Q000276:immunology; D000465:Algorithms; D000818:Animals; D000906:Antibodies; D002478:Cells, Cultured; D004032:Diet; D005260:Female; D006111:Graves Disease / Q000139:chemically induced* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D006801:Humans; D006980:Hyperthyroidism / Q000139:chemically induced* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D016131:Lymphocyte Subsets / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D011989:Receptors, Thyrotropin / Q000276:immunology*; D014807:Vitamin D / Q000378:metabolism / Q000494:pharmacology; D014808:Vitamin D Deficiency / Q000276:immunology* / Q000503:physiopathology
D000906:Antibodies; D011989:Receptors, Thyrotropin; D014807:Vitamin D; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase